Nano aluminium offers fuel cells on demand – just add water

carrrnuttt

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https://www.newscientist.com/articl...m-offers-fuel-cells-on-demand-just-add-water/

“The important aspect of the approach is that it lets you make very compact systems,” says Anthony Kucernak, who studies fuel cells at Imperial College London and wasn’t involved with the research. “That would be very useful for systems which need to be very light or operate for long periods on hydrogen, where the use of hydrogen stored in a cylinder is prohibitive.”

The discovery came in January, when researchers at the US Army Research Laboratory at Aberdeen Proving Ground, Maryland, were working on a new, high-strength alloy, says physicist Anit Giri. When they poured water on it during routine testing, it started bubbling as it gave off hydrogen.

That doesn’t normally happen to aluminium. Usually, when exposed to water, it quickly oxidises, forming a protective barrier that puts a stop to any further reaction. But this alloy just kept reacting. The team had stumbled across the solution to a decades-old problem.

Hydrogen has long been touted as a clean, green fuel, but it is difficult to store and move around because of its bulk. “The problem with hydrogen is always transportation and pressurisation,” says Giri.

Slow reaction

If aluminium could be made to effectively react with water, it would mean hydrogen on demand. Unlike hydrogen, aluminium and water are easy to carry – and both are stable. But previous attempts to drive the reaction required high temperatures or catalysts, and were slow: obtaining the hydrogen took hours and was around 50 per cent efficient.

The new alloy, which the team is in the process of patenting, is made of a dense powder of micron-scale grains of aluminum and one or more other metals arranged in a particular nanostructure. Adding water to the mix produces aluminium oxide or hydroxide and hydrogen – lots of it. “Ours does it to nearly 100 per cent efficiency in less than 3 minutes,” says team leader Scott Grendahl. Moreover, the new material offers at least an order of magnitude more energy than lithium batteries of the same weight. And unlike batteries, it can remain stable and ready for use indefinitely.

The army team has used the material to power a small, radio-controlled tank. Grendahl doesn’t see any practical issues with scaling up production to produce hundreds of tonnes of the stuff as it can be made from scrap aluminium, which is relatively cheap. The new material could power everything from laptops to buses and cars.

After reading that article, I remembered another article I read with an issue that the the above discovery can solve:

https://www.newscientist.com/articl...that-could-take-you-from-the-ground-to-space/

Plasma jet engines that could take you from the ground to space

FORGET fuel-powered jet engines. We’re on the verge of having aircraft that can fly from the ground up to the edge of space using air and electricity alone.

Traditional jet engines create thrust by mixing compressed air with fuel and igniting it. The burning mixture expands rapidly and is blasted out of the back of the engine, pushing it forwards.

Instead of fuel, plasma jet engines use electricity to generate electromagnetic fields. These compress and excite a gas, such as air or argon, into a plasma – a hot, dense ionised state similar to that inside a fusion reactor or star.

Plasma engines have been stuck in the lab for the past decade or so. And research on them has largely been limited to the idea of propelling satellites once in space.

Berkant Göksel at the Technical University of Berlin and his team now want to fit plasma engines to planes. “We want to develop a system that can operate above an altitude of 30 kilometres where standard jet engines cannot go,” he says. These could even take passengers to the edge of the atmosphere and beyond.

The challenge was to develop an air-breathing plasma propulsion engine that could be used for take-off as well as high-altitude flying.

Plasma jet engines tend to be designed to work in a vacuum or the low pressures found high in the atmosphere, where they would need to carry a gas supply. But now Göksel’s team has tested one that can operate on air at a pressure of one atmosphere (Journal of Physics Conference Series, doi.org/b66g). “We are the first to produce fast and powerful plasma jets at ground level,” says Göksel. “These jets of plasma can reach speeds of up to 20 kilometres a second (44738.7 MPH - carrrnuttt).”

To note: Earth's Escape Velocity is 11.2 kilometers per second or 25053.69 MPH

So the issue and what the first breakthrough can can solve:

The biggest limitation, though, is the lack of lightweight batteries. A huge amount of electricity is required to generate and sustain the plasma. “An array of thrusters would require a small electrical power plant, which would be impossible to mount on an aircraft with today’s technology,” says Dan Lev from the Technion-Israel Institute of Technology. The power supply is also a barrier to making the individual thrusters bigger. Doing so would reduce the number needed to propel a plane, but each would require more power.
 
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